Mohammed Alshamrani said he was left “infuriated” earlier this year when an instructor referred to him using the mocking nickname, according to the New York Times.
“I was infuriated as to why he would say that in front of the class,” Alshamrani said, according to a summary of his complaint.
Although the complaint said the derogatory nickname was “Porn Stash”, he appeared to mean “pornstache”, referring to a style of thick moustache associated with porn actors.
The incident reportedly took place at the end of a meteorology class, when an instructor asked students if they had any questions.
The instructor then apparently turned to Alshamrani and addressed him by the nickname.
“Laughing, he continued to ask, ‘What? Have you not seen a porn star before?’” Alshamrani wrote in the complaint, according to the Times.
“After I did not respond, he just let go of the subject.”
Managers for CAE USA, which provides training to civil and military aviation students, offered to have the instructor apologise but the Saudi trainee turned that offer down, according to the Times.
The FBI declined to comment to the Times on the incident, which occurred in April, and investigators are still searching for a motive for the attack after Alshamrani was shot dead at the scene.
It is not thought at this time that the derogatory comment is connected to the shooting.
However, the incident was reportedly serious enough that two American students helped Alshamrani file his complaint.
US media has reported that the Saudi gunman played mass shooting videos to others at a dinner days before the attack, according to an anonymous source briefed on the investigation.
A Twitter account which appears to match Alshamrani’s identity has also been flagged after anti-US posts were discovered on it.
In one post, which quoted Osama Bin Laden, the user accused the US of “committing crimes not only against Muslims but also humanity.”
FBI officials have conducted interviews with people who may have had contact with Alshamrani in an attempt to establish a motive for the gunman, who is thought to have acted alone.
Alshamrani began training with the US military in August 2017 and was scheduled to complete his training in August 2020, according to the Pentagon.